10,068 research outputs found
Enhancing the area of a Raman atom interferometer using a versatile double-diffraction technique
IIn this paper we demonstrate a new scheme for Raman transitions which
realize a symmetric momentum-space splitting of , deflecting the
atomic wave-packets into the same internal state. Combining the advantages of
Raman and Bragg diffraction, we achieve a three pulse state labelled
interferometer, intrinsically insensitive to the main systematics and
applicable to all kind of atomic sources. This splitting scheme can be extended
to momentum transfer by a multipulse sequence and is implemented
on a interferometer. We demonstrate the area enhancement by
measuring inertial forces
Sensitive gravity-gradiometry with atom interferometry: progress towards an improved determination of the gravitational constant
We here present a high sensitivity gravity-gradiometer based on atom
interferometry. In our apparatus, two clouds of laser-cooled rubidium atoms are
launched in fountain configuration and interrogated by a Raman interferometry
sequence to probe the gradient of gravity field. We recently implemented a
high-flux atomic source and a newly designed Raman lasers system in the
instrument set-up. We discuss the applications towards a precise determination
of the Newtonian gravitational constant G. The long-term stability of the
instrument and the signal-to-noise ratio demonstrated here open interesting
perspectives for pushing the measurement precision below the 100 ppm level
Determination of the Newtonian Gravitational Constant Using Atom Interferometry
We present a new measurement of the Newtonian gravitational constant G based
on cold atom interferometry. Freely falling samples of laser-cooled rubidium
atoms are used in a gravity gradiometer to probe the field generated by nearby
source masses. In addition to its potential sensitivity, this method is
intriguing as gravity is explored by a quantum system. We report a value of
G=6.667 10^{-11} m^{3} kg^{-1} s^{-2}, estimating a statistical uncertainty of
0.011 10^{-11} m^{3} kg^{-1} s^{-2} and a systematic uncertainty of
0.003 10^{-11} m^{3} kg^{-1} s^{-2}. The long-term stability of the instrument
and the signal-to-noise ratio demonstrated here open interesting perspectives
for pushing the measurement accuracy below the 100 ppm level.Comment: 4 figure
Atom interferometry in an optical cavity
We propose and demonstrate a new scheme for atom interferometry, using light
pulses inside an optical cavity as matter wave beamsplitters. The cavity
provides power enhancement, spatial filtering, and a precise beam geometry,
enabling new techniques such as low power beamsplitters (), large momentum transfer beamsplitters with modest power, or new
self-aligned interferometer geometries utilizing the transverse modes of the
optical cavity. As a first demonstration, we obtain Ramsey-Raman fringes with
contrast and measure the acceleration due to gravity, , to
resolution in a Mach-Zehnder geometry.
We use cesium atoms in the compact mode volume (
waist) of the cavity and show trapping of atoms in higher transverse
modes. This work paves the way toward compact, high sensitivity, multi-axis
interferometry.Comment: 5 pages, 6 figure
How to estimate the differential acceleration in a two-species atom interferometer to test the equivalence principle
We propose a scheme for testing the weak equivalence principle (Universality
of Free Fall) using an atom-interferometric measurement of the local
differential acceleration between two atomic species with a large mass ratio as
test masses. A apparatus in free fall can be used to track atomic free-fall
trajectories over large distances. We show how the differential acceleration
can be extracted from the interferometric signal using Bayesian statistical
estimation, even in the case of a large mass and laser wavelength difference.
We show that this statistical estimation method does not suffer from
acceleration noise of the platform and does not require repeatable experimental
conditions. We specialize our discussion to a dual potassium/rubidium
interferometer and extend our protocol with other atomic mixtures. Finally, we
discuss the performances of the UFF test developed for the free-fall (0-g)
airplane in the ICE project (\verb"http://www.ice-space.fr"
Effective velocity distribution in an atom gravimeter: effect of the convolution with the response of the detection
We present here a detailed study of the influence of the transverse motion of
the atoms in a free-fall gravimeter. By implementing Raman selection in the
horizontal directions at the beginning of the atoms free fall, we characterize
the effective velocity distribution, ie the velocity distribution of the
detected atom, as a function of the laser cooling and trapping parameters. In
particular, we show that the response of the detection induces a pronounced
asymetry of this effective velocity distribution that depends not only on the
imbalance between molasses beams but also on the initial position of the
displaced atomic sample. This convolution with the detection has a strong
influence on the averaging of the bias due to Coriolis acceleration. The
present study allows a fairly good understanding of results previously
published in {\it Louchet-Chauvet et al., NJP 13, 065025 (2011)}, where the
mean phase shift due to Coriolis acceleration was found to have a sign
different from expected
Improving Raman velocimetry of laser-cooled cesium atoms by spin-polarization
We study the peformances of Raman velocimetry applied to laser-cooled,
spin-polarized, cesium atoms. Atoms are optically pumped into the F=4, m=0
ground-state Zeeman sublevel, which is insensitive to magnetic perturbations.
High resolution Raman stimulated spectroscopy is shown to produce
Fourier-limited lines, allowing, in realistic experimental conditions, atomic
velocity selection to one-fiftieth of a recoil velocity.Comment: 12 pages, 6 figures, Elsevier style, to appear in Opt. Commu
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